1.6 cylinder head

ralt · Postby **ralt** » Wed Oct 19, 2011 9:30 pm

Hi.
Looking for some information on 1.6 cylinder heads.
My car has the full Loch Stewart conversion- headers, exhaust and air box.
The headers have two holes on the top of flange front and rear with only one stud. However there is a taped drilling for a stud front and rear in the cylinder head. Is this normal or was there a change in stud arrangements during the life of the 1.6?

ralt · Postby **ralt** » Thu Oct 20, 2011 5:34 pm

Hi again.
I think i have resolved the query re extra stud in each end of my 1.6 cylinder head.
I used to own 2 mazda bfmr 1.6t 4 wheel drive familias and as i still have spares for these cars and a nagging feeling i had seen the extra stud holes before. A search located a new turbo exhaust manifold gasket. It has the extra holes which means i have a b6t head on my car.
As the b6t has a static cr ratio of 7.4 and i believe b6 has 9.4 is it only the pistons crowns which determine the difference or are the combustion chamber volumes different. If the volumes are some of the reason cylinder head modification could be more creative.
I guess only a head off and measure up will provide the answers or a compression test first.
Is any one familiar with this modification?

93_Clubman · Postby **93_Clubman** » Fri Oct 21, 2011 10:55 am

ralt wrote:As the b6t has a static cr ratio of 7.4 and i believe b6 has 9.4 is it only the pistons crowns which determine the difference or are the combustion chamber volumes different.

Pistons according to Solomiata - see para 3: http://www.solomiata.com/Mx5Engine.html

'project.r.racing' on this forum, also in SE QLD, knows more about the broader use of B6 & BP motors than just in MX5s.